The subject matter of the present disclosure broadly relates to the art of vehicle suspension systems and, more particularly, to a gas spring assembly that includes a two-piece piston assembly capable of retaining a flexible wall thereon while the gas spring assembly is undergoing a tension load. The subject matter of the present disclosure also relates to a method of assembling such a gas spring assembly.
Wheeled motor vehicles of most types and kinds include a sprung mass, such as a body or chassis, for example, and an unsprung mass, such as two or more axles or other wheel-engaging members, for example, with a suspension system disposed therebetween. Typically, a suspension system will include a plurality of spring devices as well as a plurality of damping devices that together permit the sprung and unsprung masses of the vehicle to move in a somewhat controlled manner relative to one another. Movement of the sprung and unsprung masses toward one another is normally referred to in the art as jounce motion while movement of the sprung and unsprung masses away from one another is commonly referred to in the art as rebound motion.
In many applications and uses associated with wheeled motor vehicles, the suspension system of the vehicle is adapted and arranged such that there are substantially no operating conditions, during normal usage, under which the plurality of spring devices would be tensioned or otherwise undergo a tension load. That is, the configuration and/or use of conventional suspension systems is such that the spring devices are used in compression under essentially all operating conditions. In such operating environments, it is possible to utilize a gas spring assembly that has a simplified construction and minimal retention (in the direction opposite that associated with normal use) of the flexible wall thereof on the piston of the gas spring assembly. As a more-specific example, a construction can be used in which an open end of the flexible wall thereof is “snapped-on” or otherwise press-fit onto the piston of the gas spring assembly. It will be appreciated that such “snap-on” constructions can result in lower cost gas spring assemblies, at least in part, because a reduced number of components can be used and also because simplified assembly and other manufacturing techniques can be employed.
This “snap-on” interengagement between the open end of the flexible wall and a portion of the piston normally provides sufficient retention for handling and installation purposes. It will be recognized, however, that such constructions are poorly suited for applications in which the gas spring assembly will be stretched or otherwise placed in tension, as this could generate an undesirable separation between the flexible wall and the piston of the gas spring assembly.
Another example of a known construction that utilizes a simplified connection between the flexible wall and the piston of the gas spring assembly includes a clip ring that is removably secured on the piston. The open end of the flexible wall is press-fitted onto the mounting area of the piston. The clip ring is then snapped or otherwise removably secured on the end of the piston adjacent the mounting area with a portion of the clip ring contacting the flexible wall to maintain the same in position, such as during handling and installation. Typically, however, known clip rings are not suitable for providing sufficient support to withstand a tension load being applied to the gas spring assembly without an undesirable separation between the flexible wall and the piston. Accordingly, such constructions are not known or believed to be used in applications in which tension loads occur.
It is desirable to develop a simplified gas spring construction that overcomes the foregoing problems and difficulties while maintaining a relatively low cost of manufacture and ease of assembly.